Video conferencing systems have been developed which allow two-way audio and video communications between participants at remote locations. Participants may, through a common digital transmission network, participate in a real time videoconference with the assistance of cameras, microphones and appropriate hardware and software connected to the computer network used. Videoconferences can be used to present seminars or other types of presentations where additional media such as slides or documents may also be supplied to a further input system or document camera for integration into the video or data stream sent.
As the participants of videoconferences interact in real time with one another, this places a high demand on network bandwidth with the transmission of audio visual content signals. Furthermore, there can be some quality problems with the audio visual content of the conference if the network employed does not have sufficient bandwidth required to run the conference correctly. In such instances the internet protocol packets which make up the stream of signals between participants can be lost or late arriving to a receiver and hence cannot be integrated effectively in real time into the video and audio played out.
In some instances it is also preferable to supply or stream these video conferencing signals to additional observers who cannot necessarily participate in the conference. These observers may, for example, be interested in a seminar or presentation made but may not necessarily need to, or be able to, attend or participate in the conference in real time. Additional observers may view a stream of audio visual signals in real time as the conference occurs, or alternatively can view this information at a later time as their participation within the conference is not required. This stream may also be made available to conference participants at a later time.
To stream videoconference content to additional observers the signals generated are normally supplied to an additional encoding computer system. Using current technology such a computer is supplied with an analogue feed of the video and audio signals sourced from videoconference unit cameras and microphones, which subsequently converts, encodes or formats this information into a digital computer system file which can be played by specific software player applications. The actual encoding or formatting applied will depend on the player application which is to subsequently play or display the encoded videoconference. As can be appreciated by those skilled in the art, this encoded information may be streamed or transmitted out to observers in real time, or alternatively may be stored for later transmission to observers.
However, this approach used to encode videoconference content for additional observers suffers from a number of problems.
In the first instance there are losses in accuracy or quality in the resulting formatted output due to the conversion of digital audio and video information to an analogue format for subsequent supply to the encoding computer system. In turn the computer system employed converts these analogue signals back into digital format, resulting in quality and accuracy losses with each conversion made.
Furthermore, the encoding computer used must be provided with an analogue cable connection to the video conferencing equipment and thereby in most instances must also be located within a room in which one end point of the videoconference is to take place. This requires a further piece of apparatus to be located within the video conferencing room or suite, which must also be set up and configured prior to the conference in addition to the video conferencing equipment itself.
One attempt to address these issues has been made through use of video conferencing transmission protocol, being ITU H.323 entitled “Packet-Based Multi-Media Communication System”. This protocol allows audio visual signals and associated protocol information to be transmitted to a network address from the video conferencing equipment employed—without this network address acting as a full participant to the videoconference call taking place. The additional connection can be described as a streaming end point for the videoconference signals which can be supplied to the digital audio and visual information required, without the necessary digital to analogue to digital conversions required using existing technology.
However, a major complication with the use of this basic protocol arises from the high bandwidth requirements employed in the video conferencing call, and a subsequent streaming of signals to the end point at high bit rates. When re-transmitted to software player applications, the higher bit rate of the supplied input will be present in the output produced, thereby resulting in a large video file or high bandwidth requirements, which cannot readily be accessed by low speed connections to the computer network employed.
An improved audio visual media encoding system which addressed any or all of the above problems would be of advantage. A system would could act as an end point for conference calls and could encode or format audio and videoconference content for subsequent streaming or supply to observers across multiple bitrates would be of advantage. A system which could exhibit and provide flexibility and functionality regarding how these video and audio signals are encoded and supplied to observers would be of advantage.
All references, including any patents or patent applications cited in this specification are hereby incorporated by reference. No admission is made that any reference constitutes prior art. The discussion of the references states what their authors assert, and the applicants reserve the right to challenge the accuracy and pertinency of the cited documents. It will be clearly understood that, although a number of prior art publications are referred to herein, this reference does not constitute an admission that any of these documents form part of the common general knowledge in the art, in New Zealand or in any other country.
It is acknowledged that the term ‘comprise’ may, under varying jurisdictions, be attributed with either an exclusive or an inclusive meaning. For the purpose of this specification, and unless otherwise noted, the term ‘comprise’ shall have an inclusive meaning—i.e. that it will be taken to mean an inclusion of not only the listed components it directly references, but also other non-specified components or elements. This rationale will also be used when the term ‘comprised’ or ‘comprising’ is used in relation to one or more steps in a method or process.
It is an object of the present invention to address the foregoing problems or at least to provide the public with a useful choice.
Further aspects and advantages of the present invention will become apparent from the ensuing description which is given by way of example only.